I remember it being a somewhat entertaining read (been years since I looked at it) and if all you want is to get inside Gus's head and find out why he did specific things then it could be worth a look.
If you're looking at it as an educational resource to make your own game better though... n'yeah, I wouldn't bother. First of all it's several years old and the game has changed a bit in that time. Second, it's specific to high-stakes MTT play and chances are that's not what you're playing in.
Third, and probably most importantly, Gus's play style (for better or worse) is very specifically structured around his image as a maniac player, and the fact that everyone else at the table was aware of that image. It's not really something an ordinary player can take and directly apply online or in their local casino.